no of course not lou - I mean we're all online and we're not all nutters.
my point isn't so much that this guy could be a nutter, but it's very very easy to be swept away in the whole idea of the internet romance. Guy appears nice, says the things you want to hear, is supportive, but in reality you can have no idea what an actual, physical, relationship will be like until you have met in person, and therefore saying that you are leaving your partner and going to be with someone else that you've never actually met isn't wise.
He might be the loveliest man in the world on paper, he might have the loveliest personality, but you cannot possibly know that you will be physically attracted to someone you've never met.